From the Lawrence Daily Journal-World for April 9, 1972:

Arbor Day was fast approaching, and it was a special one this year — the centennial of the first observance of the day dedicated to planting trees. In discussing “tree awareness” — the theme for Lawrence Arbor Day 1972 — George Osborne, forester with the city’s parks and recreation department, mentioned that Lawrence had an estimated 60,000 trees, about 18,000 of which were in parks and on the public right of way. By “tree awareness,” Osborne said, he meant an appreciation of the worth of trees and an increased knowledge about them. He hoped that Lawrence residents would observe the day by making an effort to enjoy trees, perhaps even planting one. “Just being out on a nice day and enjoying the trees around us can be a pleasant and informative way to enjoy Arbor Day,” he said.